Layout 1 Thematic Section: Advances in Musculoskeletal and Neuromuscular Rehabilitation | Maccarone & Masiero Eur J Transl Myol 34 (2) 12167, 2024 doi: 10.4081/ejtm.2024.12167 Lumbar Spinal Stenosis (LSS) is a pathological process where bony, ligamentous, and synovial elements of the lower axial spine degenerate and overgrow, progressively compressing the neural and vascular elements in the spinal canal.1 This degenerative process consists of one of the most diagnosed spinal disorders in older adults and may result in the impingement of the nerve roots of the cauda equina. Although the pathophysiology of the clinical syndrome is not well understood, a narrow central canal or intervertebral foramen is an essential defining feature. In the case of degenerative lumbar spinal stenosis, the most common form of lumbar stenosis, disc degeneration, thick- ening and buckling of the ligamentum flavum and facet hy- pertrophy contribute to canal narrowing. Congenital factors may predispose some individuals to this condition: disc degeneration has a substantial genetic com- Abstract Lumbar spinal stenosis (LSS) occurs when bony, ligamentous, and synovial elements of the lower axial spine degenerate and overgrow, compressing neural and vascular elements in the spinal canal. Compression can cause static back pain, radicular lower extremity pain, or neurogenic claudication. Radiological and clinical findings are needed to diagnose lumbar stenosis. In this framework, caudal epidural steroid injection (ESI) is a standard treatment. The volume injected and needle positioning are the main issues that could compromise the effectiveness of the epidural injection. However, ultrasound-guided caudal epidural injections have become more common in recent years. Since Klocke and colleagues described the ultra-sound-guided caudal block in 2003, it has grown in popularity. Multiple ethnic studies have reported ultrasound-guided caudal injection success rates of 96.9–100%. Color Doppler ultrasonography can also determine if a drug solution reaches the lumbosacral region. We enrolled 42 patients with lumbar spinal stenosis, persistent lumbosciatalgia, and neurogenic claudicatio unresponsive to painkillers who were not surgical candidates. Each patient receives four weekly injections for four weeks. If the patient responds to treatment but still has pain, monthly injections are needed to reach and maintain the benefit. Treatment will be changed if the patient does not respond after 4 caudal injections. Sterile caudal epidural injections are performed with ultrasound guidance and a spinal needle 21G. Triamcinolone 40 mg, levobupivacaine 10 mg, and physiological solution 10 ml are delivered. Each patient received an average of 4 injective treatments (4±2, Means 4, SD 2). Data analysis shows that the treatment reduced pain significantly before and after therapy, which persisted after 3 months. Caudal epidural injection is one of the most common conservative treatments for chronic low back pain with radiculopathy, and lidocaine alone or with steroids is effective. In this framework, the two main literature issues about caudal epidural injection effectiveness on lumbar pain are correct. Therefore, 10 ml is suitable and effective for treating symptoms without side effects. Pain reduction of over 50% from start to finish and three-month follow-up have shown significant results in pain control and disability improvement. Finally, caudal epidural injection for lumbar spinal stenosis symptoms is effective, safe, and provides long-term pain relief. Key Words: caudal epidural injection, lumbar spinal stenosis, ultrasound guidance. Eur J Transl Myol 34 (2) 12167, 2024 doi: 10.4081/ejtm.2024.12167 Ultrasound-guided caudal epidural injection to treat symptoms of lumbar spinal stenosis: a retrospective study Veronica Gagliardi,1,2 Antonello Lovato,1 Francesco Ceccherelli,1 Giuseppe Gagliardi3 1AIRAS Padova, Italy; 2Department of Medicine, University of Padua, Italy; 3Department of Anesthesiology, Intensive Care and Pain Medicine, Rovigo Hospital, aULSS5 Polesana, Rovigo, Italy. This article is distributed under the terms of the Creative Commons Attribution Noncommercial License (CC BY-NC 4.0) which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author(s) and source are credited. - 116 - Non -co mmerc ial us e o nly Ultrasound-guided caudal epidural injection in the treatment of lumbar spinal stenosis Eur J Transl Myol 34 (2) 12167, 2024 doi: 10.4081/ejtm.2024.12167 ponent, but less is known about the degree to which genes influence other contributors to degenerative stenosis or as- sociated central spinal canal dimensions. Findings on imaging are scarcely correlated with symptoms and disability. There may be neurovascular or inflammatory factors or other mediators that cause symptoms to manifest in association with a narrow canal, which may have differ- ent genetic and environmental influences.2 The compression can be either asymptomatic if mild or it can result in a variable combination of static back pain, rad- icular lower extremity pain, or neurogenic claudication. The diagnosis of lumbar stenosis can be difficult and involves a combination of radiological and clinical findings. Treatment ranges from conservative measures with physical therapy and core strengthening, to steroid injections in the facet joints or in the epidural space, to a more radical solu- tion with surgical decompression.1 In this framework, caudal epidural steroid injection (ESI) is an established treatment for spine-related problems.3,4 Caudal access to epidural space is considered a rapid and advantageous technique:3 i) caudal entry into the epidural space is relatively easy and there is very little risk of dural puncture; ii) it is not expensive; iii) it can be used in patients suffering from coagulopathies. The main problems that could impair the effectiveness of the treatment with epidural injection are the volume injected and the correct positioning of the needle.5 Caudal epidural injection could be performed using an- atomical landmarks, but the risk of failure is high.6 There- fore, a guide tool is necessary to achieve the aim.7,8 The percentage of unsuccess in the absence of fluoroscopic guidance was reported in 9% to 38% of cases. This has caused many authors to recommend the use of fluoroscopy to perform epidural injections and it is considered the tech- nique of first choice for accurate needle placement,9 even though this does not assure either targeted delivery or ac- curate placement of the drug.10 Nevertheless, in the last years is even more frequent the use of ultrasound-guided technique to execute the caudal epi- dural injection. The ultra-sound-guided block was first de- scribed by Klocke and colleagues in 2003, and has, since then, gained increasing popularity. Several studies from var- ious ethnic populations have repeatedly reported very high successful rates (96.9– 100%) of ultrasound-guided caudal injection.2 Yoon and colleagues11 used color Doppler ultrasonography guidance to position the needle during ESI and to visualize any vascular intake of the medication. The needle position was then verified using an injection of a contrast dye and fluoroscopy. Under ultrasound guidance, the correct place- ment of the needle was confirmed by fluoroscopy in 50 of the 52 successfully injected patients. The accuracy of steroid injection into the caudal space using ultrasound guidance was comparable with that obtained using fluoroscopic guidance. Moreover, Color Doppler ul- trasonography guidance allows to determine whether a drug solution reaches the lumbosacral region.12 Another debated issue is the entity of the volume injected: volumetric caudal injections have been examined by epi- durography by Kim et al. who found no advantage in terms of cephalic migration of injectate, despite using incremental volumes up to 50 ml,13 but there is evidence that an injected volume of 20 ml spread to a level varying from L5 and T9, with a median value of L3.14 Aim of the study The study aims to assess the effectiveness of caudal epidu- ral injection with corticosteroid and local anesthetic in a standard volume using ultrasound guidance for the injection to treat symptoms related to lumbar spinal stenosis, not eli- gible for surgical treatment. Materials and Methods We have enrolled 42 patients with the diagnosis of lumbar spinal stenosis, with persistent lumbosciatalgia and neu- rogenic claudicatio unresponsive to pharmacological therapy. Exclusion criteria are the following: i) age <18 years; ii) current coagulopathic diseases; iii) injuries of spinal me- dulla; iv) current infections; v) uncontrolled diabetes mel- litus; vi) uncontrolled hypertension; vii) uncontrolled glaucoma; viii) peripheral myelopathy and peripheral neu- ropathy; ix) previous spine surgery is not an absolute con- traindication. Statistical analysis The details of the statistical analysis conducted can be seen in Table 1 and Figure 1. Assessment of the pain To quantify the pain, we use the NRS scale, and the sub- jective improvement is measured using the Subjective Rating Scale of function recovery. The above-mentioned scale consists of 5 levels, which correspond to the follow- ing points: 0=no recovery, 1=slight recovery, 2=moderate recovery, 3=good recovery, and 4=excellent recovery. The subjective improvement is measured using the Func- tional Rating Index (FRI), which contains 10 items that measure both pain and function of the spinal musculos- keletal system. Of these 10 items, 8 refer to activities of daily living that might be adversely affected by a spinal condition, and 2 refer to two different attributes of pain. Because many spinal disabilities are most likely a combi- nation of loss of function and pain and/or the fear of pain, using both pain and function allows for a wider view of a patient’s disability.10 Using a 5-point scale for each item, the patient ranks his or her perceived ability to perform a function and/or the quantity of pain at present ("right now") by selecting one of the five response points that are anchored by bipolar statements (0 =no pain or full ability to function); 4= worst possible pain and/or unable to perform this function at all). When all 10 items are completed, the FRI score is cal- culated as follows: (total score / 40) x 100% (Table 2).15 Furthermore, all patients undergo the Oswestry Disability Index 2.1°, Versione Italiana (ODI-I) before the treatment, after the treatment, and in the follow-up evaluation at 3 months. - 117 - Non -co mmerc ial us e o nly Ultrasound-guided caudal epidural injection in the treatment of lumbar spinal stenosis Eur J Transl Myol 34 (2) 12167, 2024 doi: 10.4081/ejtm.2024.12167 - 118 - Table 1. Statistical analysis. ODI-I: ODI-I: FRI: FRI NRS NRS H0 Score pre= H0 Score H0 Score pre= H0 Score H0 Score pre= H0 Score Score post Follow-up Score post Follow-up Score post Follow-up =Score pre =Score pre =Score pre H1 Score pre≠ H1 Score H1 Score pre≠ H1 Score H1 Score pre≠ H1 Score Score post Follow-up≠ Score post Follow-up≠ Score post Follow-up≠ Score pre Score pre Score pre n 42 patients n 42 patients n 42 patients n 42 patients n 42 patients n 42 patients t test 4.97*10–23 t test 2.41*10–20 t test 2.75*10–17 t test 1.41*10–15 t test 1.28*10–21 t test 3.55*10–17 Table 2. Functional Rating Index for neck and back problems. Pain intensity 0: no pain 1: mild pain 2: severe pain 3: severe pain 4: worst possible pain Sleeping 0: perfect sleep 1: mildly 2: moderated 3: greatly 4: totally disturbed disturbed sleep disturbed sleep disturbed sleep sleep Personal care 0: no pain, 1: mild pain, 2: moderate pain, 3: moderate pain, 4: severe pain, no restriction no restriction need to go slowly need some need 100% assistance assistance Travel 0: no pain 1: mild pain 2: moderate pain 3: moderate pain 4: severe pain on lingo trips on long trips on long trips on short trips on short trips Work 0: can do usual 1: can do usual 2: can do 50% 3: can do 25% 4: cannot work work plus work, no extra of usual work of usual work unlimited extra work work Recreation 0: can do 1: can do 2: can do 3: can do 4: cannot do all activities most activities some activities a few activities any activity Frequency of pain 0: no pain 1: occasional pain, 2: intermittent pain, 3: frequent pain, 4: constant pain, 25% of the day 50% of the day 75% of the day 100% of the day Lifting 0: no pain 1: increased pain 2: increased pain 3: increased pain 4: increased pain with any weight with heavy with moderate with light with any weight weight weight weight Walking 0: no pain, 1: increased pain 2: increased pain 3: increased pain 4: increased pain any distance after 1 mile after ½ mile after ¼ mile with all walking Standing 0: no pain after 1: increased pain 2: increased pain 3: increased pain 4: increased pain several hours after several hours after 1 hours after ½ hour with any standing Non -co mmerc ial us e o nly Ultrasound-guided caudal epidural injection in the treatment of lumbar spinal stenosis Eur J Transl Myol 34 (2) 12167, 2024 doi: 10.4081/ejtm.2024.12167 The Oswestry Disability Questionnaire score is obtained by summing the scores of each of the 10 sections of the Ques- tionnaire, (from 0 to 5 for each one), then dividing it by the highest score possible, (50 if all the 10 sections have been completed, 45 if one of them has not been completed) then converting this value in percentage (Table 3).16 Patients included and technique employed The mean age of the above-mentioned 42 patients is 70,67 ± 10,90 years, 12 of whom are female and 30 are male. All patients have already done the electromyography and an MRI of the lumbar vertebral column to confirm the dia- gnosis. The duration of the pain is 28,7± 2,3 weeks, with an initial high intensity (NRS = 7). All patients included have previously undergone both medical and rehabilitative therapy without any benefit. The therapeutic scheme consists of 4 injective treatments once a week for 4 weeks on each patient. After these, if the pain relief is not complete but the patient is a responder to the treatment, further injections every month have to be executed: once a month to reach and maintain the benefit. If after the 4 caudal injections, the patient is a non-re- sponder, he will change therapy. The caudal epidural injection is a sterile procedure and has been executed using ultrasound guidance, using a spinal needle 21G. The Ultrasound machine employed is Samsung V6. The technique has been performed by the authors, trained in the musculoskeletal US as a guide for interven- tional treatments. The patient is positioned in a prone decubitus position with a cushion under the pelvis to better recognize the anatomi- cal landmarks. We use the linear ultrasound transducer (7- 13 MHz) firstly with a transversal scan to locate the sacral hiatus to obtain its transverse view where the two sacral cornua appear as two hyperechoic structures, and the sacral hiatus is the hypoechoic region between the 2 band-like hy- perechoic structures. At this level, the ultrasound transducer is rotated 90 degrees to obtain a longitudinal scan, to direct the needle using the "in-plane" technique through the sacral hiatus in the epidural space, visualizing the needle in real- time. The confirmation of the correct positioning is verified by visualizing the unidirectional flow of the fluid injected in the epidural space with a color-doppler image (Figure 2,3,4). Moreover, ultrasonography can also provide infor- mation regarding the cephalad spreading of injectate during caudal epidural injection. It is suggested that the advance- ment of the needle tip beyond the apex of the sacral hiatus - 119 - Figure 1. Critical values of t. Table 3. Oswestry score related to the assessment of the level of disability. Disability assessment Oswestry score (%) Minimal disability 0-20 Moderate disability 21-40 Severe disability 41-60 Crippled patients 61-80 Bed-bound patients 81-100 Non -co mmerc ial us e o nly Ultrasound-guided caudal epidural injection in the treatment of lumbar spinal stenosis Eur J Transl Myol 34 (2) 12167, 2024 doi: 10.4081/ejtm.2024.12167 should be limited to 5 mm to avoid dural puncture because the distance between the apex of the sacral hiatus and dural sac termination can be as short as less than 6 mm.17 The drugs delivered are triamcinolone 40 mg; and levobu- pivacaine 10 mg; adding physiological solution to obtain a total volume of 10 mL, regardless of the level of stenosis. A solution including Levobupivacaine with a concentration of 0,1% allows the sensory block to avoid the motor block. Neurotoxicity of steroidal drugs is not due to the steroidal molecule but to the Polyethylene glycol present in the for- mulation. Nevertheless, long-acting delivery formulations contain a percentage of Polyethylene glycol about 3%, in- ferior to the level of neurotoxicity. Epidural administration of the steroid appropriately diluted with the local anesthetic and physiological solution guar- antees a significant reduction of the neurotoxic effects of the steroid.18 Data analysis We analyze our results using the T-test for paired data. With a level of significance of 0.001, the scores of all our scales of assessment are different before and after the treatment and also in the follow-up. Results We have performed on average 4 injective treatments (4±2, Means 4, SD 2) on each patient. Data analysis shows that the treatment has been effective in pain relief, detecting a significant reduction in pain comparing the conditions be- fore and after the therapy, which also persisted in the fol- low-up after 3 months (Table 4). In the same way, the results observed in the FRI show a significant improvement comparing the beginning and the end of the treatment, maintained in the 3-month follow-up (Table 5). Eventually, the results of the ODI-I Questionnaire illustrate a significant improvement in the grade of disability: from a score indicating a grade of severe disability to a level of moderate disability (Table 6). We do not detect any complication consequent to the treat- ment performed neither immediately after nor in the fol- low-up. Discussion Caudal epidural injection is one of the most common con- servative treatments for chronic low back pain with radicu- lopathy, and it has been demonstrated that the administration of either Lidocaine alone or lidocaine in con- junction with steroids is significantly effective.19 In this framework, the two main issues discussed in litera- ture concerning the effectiveness of the caudal epidural in- jection on lumbar pain are the correct positioning of the needle and the volume injected. Our work confirmed that the ultrasound-guided injection is a safe, precise, and effective technique, representing a valid alternative to fluoroscopy: as Yoon describes, ultrasound is as reliable as fluoroscopy. The choice of the injected vol- ume is very important as the effectiveness of the block de- - 120 - Figure 2. Anatomy of the sacral hiatus. Figure 3. Position of the patient and of the US probe. Figure 4. Ultrasonographic imaging of the sacral hiatus and of the needle position (indicated by the white arrow). Non -co mmerc ial us e o nly Ultrasound-guided caudal epidural injection in the treatment of lumbar spinal stenosis Eur J Transl Myol 34 (2) 12167, 2024 doi: 10.4081/ejtm.2024.12167 pends on this parameter: if too small the block could be in- effective, if too high complications such as increased intra- cranial pressure may occur.20 The choice to administer 10 ml has been made following data reported in the literature. About this, Kim13 has ex- amined the extension of the distribution of volumes from 10 ml to 50 ml, detecting that the level reached with 10 ml was L3, and it did not vary significantly with higher vol- umes. Therefore, the volume of 10 ml has been demon- strated to be suitable and effective to treat symptoms without causing side effects. This technique allows to use of a thinner needle than the needle used for the standard lumbar epidural injection, with lower mechanical damage. The Ultrasound guide indicates the exact positioning of the needle and the exact point of injection. We do not have any short-term and long-term complications. Thus, we can con- sider this technique safe and effective. The drugs employed with the indicated volume and dosage have shown to be effective and safe. The control of the pain and the improvement of the entity of the disability have shown significant results, with a re- duction of the pain of more than 50% comparing the begin- ning and the end of the treatment, maintained also at the three-month follow-up. The judgment of the subjective pain relief and the func- tional recovery assessed using the Subjective Rating Scale of function recovery has been significant and confirmed by the results observed at the ODI-I (Oswestry Disability Index): the value at the ODI-I indicates the passage from a level of severe disability to a level of moderate disability, with a higher personal autonomy, and a considerable im- provement of the quality of life. This study has the limitations of being a retrospective ob- servational monocentric study, without comparing different groups of patients. Nevertheless, it has been planned to de- fine the adequate volume to inject, to assess the effective- ness and the safety of the technique. The psychological factors that might alter our results, such as the general over-reaction pain, have not been evaluated. - 121 - Table 4. NRS variation before the therapy, after the 1st, 2nd, 3rd treatments and at the 3 months follow-up. NRS score Basal 1st treatment 2nd treatment 3rd treatment Follow-up 3 months Mean 6.6 3.6 2.6 2.4 3.35 SD 0.84 1.26 1.17 0.96 0.94 NRS, numerical rating scale; SD, standard deviation. Table 5. FRI scale percentage variations before the therapy, at the end of the therapy, and at the 3 months follow-up. FRI % Basal % End-therapy Follow-up 3 months Mean 31.5 19.4 21.1 SD 3.16 5.31 4.73 FRI, functional rating index; SD, standard deviation. Table 6. ODI score and percentage before and after the therapy, and at the 3 months follow-up. Oswestry Score pre % pre Score post % post Score % Follow-up score Follow-up Mean 27.7 56.4 14 28.5 14.7 29.4 SD 2.71 5.12 3.88 7.82 4.08 8.16 ODI, oswestry disability index; SD, standard deviation. Non -co mmerc ial us e o nly Ultrasound-guided caudal epidural injection in the treatment of lumbar spinal stenosis Eur J Transl Myol 34 (2) 12167, 2024 doi: 10.4081/ejtm.2024.12167 Nevertheless, the aim was to assess the functional recovery, as described by the FRI scale. Conclusions In conclusion, the results have demonstrated that the treat- ment of symptoms deriving from lumbar spinal stenosis with caudal epidural injection is effective, free of effects and gives long-lasting pain relief. The ultrasound guidance represents a valid alternative to fluoroscopy, free from ion- izing radiation, and could be virtually used in any clinical setting. This treatment allows patients affected by a pathology with- out other therapeutic schemes if they are non-responders to the other described treatments, even though it is not effec- tive in the case of myelopathy. It can be performed in an outpatient setting, avoiding the operating room and the ra- diological equipment. We can also use the treatment as a maintenance to extend the benefit. This study defines the ultrasound guide as possible and de- termines the volume and the dosage of drugs, still contro- versial in the literature. List of abbreviations LSS, lumbar spinal stenosis US, Ultrasound ODI-I, Oswestry Disability Index MRI, magnetic resonance imaging NRS, numeric rating scale ESI, epidural steroid injection FRI, functional rating index Conflict of interest The authors declare no potential conflict of interest, and all authors confirm accuracy. Informed consent All patients participating in this study signed a written in- formed consent form for participating in this study. Patient consent for publication Written informed consent was obtained from a legally au- thorized representative(s) for anonymized patient infor- mation to be published in this article. Availability of data and materials All data generated or analyzed during this study are in- cluded in this published article. Corresponding Author Veronica Gagliardi, Department of Medicine, University of Padua, Italy. ORCID ID: 0000-0002-3939-8461 E-mail: veronica.gagliardi@studenti.unipd.it Giuseppe Gagliardi ORCID ID: 0000-0003-4972-1266 E-mail: giuseppe.gagliardi@aulss5.veneto.it Antonello Lovato ORCID ID: 0000-0001-5465-3646 E-mail: lovatoantonello@gmail.com Francesco Ceccherelli ORCID ID: 0000-0001-9641-8273 E-mail: fceccherelli@airas.it References 1. Bagley C, MacAllister M, Dosselman L, et al. Current concepts and recent advances in understanding and managing lumbar spine stenosis. F1000Res 20198:F1000 Faculty Rev-137. 2. Vikram K. Caudal epidural steroid injections-a mini re- view. Open Access J Neurol Neurosurg 2017;3:555606. 3. Liu K, Liu P, Liu R, et al. Steroid for epidural injection in spinal stenosis: a systematic review and meta-analy- sis. Drug Des Devel Ther 2015;9:707-16. 4. Ibrahim ME, Awadalla MA, Omar AS, Al-Shatouri M. Ultrasound-guided caudal epidural steroid injection in chronic radicular low back pain: short-term electrophy- siologic benefits. BJR Open 2020;2:20190006. 5. Kao SC, Lin CS. Caudal epidural block: an updated re- view of anatomy and techniques. Biomed Res Int 2017;2017:9217145. 6. Stitz MY, Sommer HM. Accuracy of blind versus flu- oroscopically guided caudal epidural injection. Spine (Phila Pa 1976) 1999;24:1371-6. 7. Kao SC, Lin CS. Caudal epidural block: an updated re- view of anatomy and techniques. Biomed Res Int. 2017;2017:9217145. 8. Nagpal AS, Vu T-N, Gill B, et al. Systematic review of the effectiveness of caudal epidural steroid injections in the treatment of chronic low back or radicular pain. In- tervent Pain Med 2022;4:100149. 9. Koo BS, Kang WB, Park JW, et al. Analysis of caudal epidurogram in single center: A preliminary study of lumbar radiculopathy management. Medicine (Balti- more) 2018;97:e12810. 10. Manchikanti L, Cash KA, Pampati V, et al. Evaluation of fluoroscopically guided caudal epidural injections. Pain Physician 2004;7:81-92. 11. Yoon JS, Sim KH, Kim SJ, et al. The feasibility of color Doppler ultrasonography for caudal epidural steroid in- jection. Pain 2005;118:210-4. 12. Yoo SW, Ki MJ, Doo AR, et al. Prediction of successful caudal epidural injection using color Doppler ultraso- nography in the paramedian sagittal oblique view of the lumbosacral spine. Korean J Pain 2021;34:339-45. 13. Kim KM, Kim HS, Choi KH, Ahn WS. Cephalic spreading levels after volumetric caudal epidural injec- - 122 - Non -co mmerc ial us e o nly mailto:veronica.gagliardi@studenti.unipd.it mailto:giuseppe.gagliardi@aulss5.veneto.it mailto:lovatoantonello@gmail.com mailto:fceccherelli@airas.it Ultrasound-guided caudal epidural injection in the treatment of lumbar spinal stenosis Eur J Transl Myol 34 (2) 12167, 2024 doi: 10.4081/ejtm.2024.12167 tions in chronic low back pain. J Korean Med Sci 2001; 16:193-7. 14. Cleary M, Keating C, Poynton AR. The flow patterns of caudal epidural in upper lumbar spinal pathology. Eur Spine J 2011;20:804-7. 15. Feise RJ, Michael Menke J. Functional rating index: a new valid and reliable instrument to measure the mag- nitude of clinical change in spinal conditions. Spine (Phila Pa 1976) 2001;26:78-86; discussion 87. 16. Monticone M, Baiardi P, Ferrari S, et al. Development of the Italian version of the Oswestry Disability Index (ODI-I): A cross-cultural adaptation, reliability, and va- lidity study. Spine (Phila Pa 1976) 2009;34:2090-5. 17. Kao SC, Lin CS. Caudal epidural block: an updated re- view of anatomy and techniques. Biomed Res Int 2017;2017:9217145. 18. Marinangeli F, Ciccozzi A, Donatelli F, et al. Uso degli steroidi per via spinale ed epidurale [Clinical use of spi- nal or epidural steroids]. Minerva Anestesiol 2002;68: 613-20. Italian. 19. Manchikanti L, Knezevic NN, Boswell MV, et al. Epi- dural injections for lumbar radiculopathy and spinal ste- nosis: a comparative systematic review and meta-anal- ysis. Pain Physician 2016;19:E365-410. 20. Bosscher H. Pressure-volume relationships in the spinal canal and potential neurological complications after epi- dural fluid injections. Front Pain Res (Lausanne) 2022;3:884277. Disclaimer All claims expressed in this article are solely those of the authors and do not necessarily represent those of their af- filiated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher. Submitted: 8 December 2023. Accepted: 15 February 2024. Early access: 7 May 2024. - 123 - Non -co mmerc ial us e o nly